Variable compression ratio internalcombustion engine



n INVENTOR QT. Krul ABY f" ?atente repa- 3, l

assar'zc CORESSN RATIO ENTEBNAL- This invention relates to internalcombustion engines and pertains particularly to the compression phase ofthe operation of the engine,

and in which, the principal object is to provide the conventional,multi-cylindered internal combustion engine with simple and reliablemeans to greatly improve the over all thermal eiiiciency through theentire'range of throttle operation.

A further object is to provide the engine with means to decrease thecombustion chamber volume of respective cylinders, in approximately thesame ratio that the absolute pressure in intake manifold decreases belowthe prevailing atmospheric pressure.

A still further object is to provide simple means permitting theadjustment of the'degree of compression of respective individualcylinders oi an engine to the exact compression pressure desired.

Another object is to provide for the automatic positioning or' themechanism so that a mean compression ratio will prevail as therengine isstarted, but which becomes fully eiective after a minimum time of theengines operation.

Yet another object is to employ the degree of vacuum in the plurality ofcylinders of an engine, greatly augmented by the simultaneous decreasein the intensity oi expansion pressures, to

supply the motive force necessary to'actuate the mechanism, and therebyto increase the compression ratio, resulting in an approximate constantabsolute compression pressure at all times oi engine operation.

Another further object is to provide the firing chambers withresiliently actuated means to automatically vary the size oi' thechambers with respect to the momentary torque loads of the engine.

Other objects and advantages will appear as this description progressesand by referencetc the drawing, in which- Figure i is a plan elevationof an eight-in-line, cylindered internal combustion engine, with theinvention applied thereto and forming part thereoi.

Figure 2 is an enlarged fragmentary vertical.

vsectional elevation, taken approximatelyon the line 2--2 ci Fig. l.,

Referring by numerals-to the drawing, t desig nates each of two aumliaryblocks used in this instance of showing and describing the invenl tion,as applied to a conventional four-cycle intornai combustion engine,said' blocks being used in place of the cylinder head blocks of theconventional engine.

Each block t is provided with its plurality of cylinders ai, each ofwhich when the blocks are I mounted and secured in place on the enginecylinder block or blocks 5, alining with respective i6, said lever italso being keyed to the shaft ll.

The remaining links 9 of respective pistons i are connected at theirupper ends to respective short levers il, keyed to the shaft H. j

The long end of the lever l2 is provided on its free end with anadjustable pusher pin i8 in en gagementwth the depression is of a saddle2t on the upper end of an expansion coil spring 2l, the lower end ofsaid spring being seated in a saddle 2i within an inverted piston 23which is reciprocally mounted in c, cylinder 2t, supported from one ofthe blocks Upper and lower adjustable stops 25 and 2e' respectively ofay supporting bracket 2l are provided for limiting the swinging travelof the lever l2, said bracket being mounted on one of the blocks Si.

Provision is made for maintaining a'n oil body in the space 2t beneaththe piston 23 in the cylinder 2d, through the oil line 2t from theoiling system (not shown) of the engine, whenthe engine is operating.

In practicing the invention, when the engine is stopped, the spring 2lwill force the lever i2 upwardly against the stop 2t, and consequently,all of the pistons l will be lnoved to maximum lowered positions in thecylinders t by the rocking or the shaft il, thereby decreasing the size.

of the tiring chambers to points ofgreatest compression ratio, as wouldbe required to approximate designed compression at idling operation'orthe engine, and at which position the adjustable stop 25 is nxed.

Simultaneous with the spring 2i forcing the' lever i2 against the stop25 the spring will force the piston 23 down in the cylinder 21.3 as `theoil therebeneath leaks back to the crank case through the oil line 29,and the free length of the spring will be approximately attained whenthe piston 23 seats against the 'bottom wall of the cylinder 2t, asshown in dotted lines in Fig. 2.

The instant the engine is started, the' compression pressure against thepistons 1 will rock the shaft II `and cause the spring end of the leverI2'to bear against the unloaded spring 2l and start to compress it.Before any of the cylinders have iired, the lever I2 will have moved theapproximate half of its normal operative range of travel in compressingthe spring to its initial operative tension, and upon succeedingrevolutions of the engine crank-shaft with normal ignition of all ofthe-cylinders 6, the lever I2 will be completely moved against thebottom stop 26,.

which limits the degree of outward movement of the pistons 1, topositions of least compressionr ratio as required to provide the desireddegree of compression, permitted by the fuel used. As the engine isstarted to idling, the lever I2 will be returned to a positiondetermined by the initial spring tension.'

The lever I5`of the dash-pot I6, being connected to the torque shaft Il,dampens out the inter-cyclic rocking movement impulses of .the shaft Il,so that lthe mean average of the sum of the impulses-will be required tobe counterbalanced by the tension of the spring 2l. The action of thetension of the spring 2l and the dash-pot I6, on the rocking of theshaft Il, results in no movement of the shaft Il and the pistons 1linked Lthereto, unless a change in en# gine torque occurs.

During the initial idling period of the engine, the lubricating oil pumpof the engine, will force Aoil up under the piston 23, thus graduallymoving the partly compressed spring 2| outwardly until the piston 23reaches the stop-ring 3U, at the outer end of the cylinder 24, and atwhich time the lever I2 will be in a position near the upper stop 25,because the initial spring pressure at the spring end of the lever, willjust balance the combined opposed turning eort on the shaft I I,consisting of the algebraic sum of the gas pressures of all of thepistons 1 on their respective short lever connections with the shaft II.Thus, as the engine was idling, the oil pressure from the oil line 29.inraising the spring piston 23, also raised the spring end of the lever I2 which caused the 'cylinder head pistons 1 to be moved to positions ofminimum combustion chamber volume in respective firing chambers 8 forproviding a maximum compression ratio for eiiicieni; idling operation oftheengine.

When the engine throttle (not shown) is opened.

be effective in causing the spring 2| to move the pistons 1 inwardly.Any throttling effect, incidental or intentional, will obviously cause adecrease in the sum of gas pressures on the pistons 1, with aproportionate decrease in the torque output of the engine, and thespring tension will then relocate the lever I2 to just balance thesmaller forces on the pistons 1 and in so doing, relocate said pistonsto positions vof greater compression ratio. Thus, since the enginetorque output is approximately directly proportional to forces on thepistons 1, it is obvious that the automatically selected compressionratio will vary inversely proportionate to the torque output of theengine.

By utilizing the varying gas pressures as well as the varying vacuums intherespective operating cylinders, an extremely simple, reliable andeiiicient mechanism is provided, whereby the corrective forces are largecompared to the small inherent friction of the simple linkages used. Duetherefore, to the simple mechanism disclosed, automatically selected,varying compression ratios, will instantaneously and reliably remainadjusted to the highest values as indicated for best thermal efliciency,and should border-line knocking occur, the greatly increased combustionchamber pressures in effecting an enlargement of the combustion chambervolumes, inherently removes the primary cause.

The adjustable links 9 permit exact equalization of individual cylindercompression, and the entire engine compression range can be adjusted upor down, and to meet final requirements forfne or minute changes, theadjustable pusher pin I8 on the spring end of the lever I2 is provided,-

which when adjusted will be effective on all of the pistons 1 and theirrespective cylinders 6, with respect to cylinder compression.

The use of the dash-pot I6 in conjunction with the shaft II, willdampen-out pulsation at the lever l2, and the oil body beneath thepiston 23 which is drained at times of engine shut-down for unloadingthe spring 2I, while not essential a small degree, the cylinderpressures of all cylinders during all cycles of operation increase acommensurate degree, as the vacuum created during suction strokesis'less intense, the compression resistance greater, as well as theexpansion pressures being greater.

In addition, there will be some increase in cylinder gas pressures whileexhausting spent -gas charges, thus the algebraic sum of instantaneouscylinder pressures will increase and result in rcking the shaft II untilthe increased compression on the spring 2| will just counterbalance theincreased forces on the pistons 1, and simultaneduring normal operation,does assure a most prompt outward movement of the pistons 1, during thefirst 1A revolution of starting the engine, to eliminate possibleexcessive compression and pre-ignition at initial starting operation.

While an embodiment of the invention is here shown and described,obviously many others may occur to those skilledin the particular art.I, therefore, do not limit myself to the details described, but claim asmy invention all variations and modifications within the scope of thesubjoined claims. e

What I claim is:

1. A cylinder for an internal combustion engine having a movable wallwith manually adjustable means therefor, and automatically actuatedmeans cooperable to move said wall between adjustably xed positions.

2. A cylinder for an internal combustion engineV having a manuallyadjustable movable wall in axial alinement with the cylinder,automatically actuated means cooperable to move said wall to decrease orincrease the ring chamber of the cylinder and a pair of adjustablelimiting stops cooperable with said means.

forming a part of the ilring chamber thereof, and spring actuatedlinkage cooperable with said wall to move it between iixed predeterminedpositions.

A5. A multi-cylindered internal combustion en- -ginev having a manuallyadjustable movable wall chambers.

6. A multi-cylindered internal combustion eri-- gine having a manuallyadjustable movable wall formingl a part of the firing chamber of' eachcylinder, and spring actuated means cooperable to 'move all of saidwalls either inwardly or outwardly to vary distances in respectivefiring chambers.

7. A multi-cylindered internal combustion engine having a manuallyadjustable movable wall in axial alinement with respective cylinders andforming `a part of the iiring chamber of each cylinder, and 'resilientlyactuated linkage cooperable to move all of said walls either inwardly oroutwardly of respective cylinders.

8. A multi-cylindered internal combustion engine having manuallyadjustable cylinder heads, spring actuated linkage cooperable to movesaid heads varying distances between adjustably iixed stops, and apulsation eliminator cooperable with said linkage. f

9. A multi-cylindered internal combustion engine having movable cylinderheads, a rock shaft, individually adjustable linkage connecting saidheads to the rock shaft, and a spring actuated lever connected to saidrock shaft having adjusting means at one end thereof.

10. A multi-cylindered internal combustion engine having movablecylinder heads, a rock shaft, individually adjustable linkage connectingsaid heads to the rock shaft, a spring actuated lever connected tosaid'rock shaft having adjusting means at its extending end, and a uidactulnder, and a coil'spring cooperable at 'one end with said piston andat its other end with said lever.

cylinder and a communicating firing chamber, a

movable head in said flring chamber, a lever connected to said head, acylinder having an oil pressure supply source. a pistonin said oi1cylinder adapted to be actuated bythe oil pressure therein, a coilspring interposed between said lever and said piston, and a piston stopat the Outer end of said oil cylinder.

14. A cylinder foran internal combustion engine having a. movable wall,automatically actu- Aatedlmeans cooperable to move said wall topositions intermediate its movable length, and-other means effective onsaid rst means during starting of the engine.

15. The methodof operating a variable compression ratio internalcombustion engine, consisting of the automatic selection of apredetermined minimum compression ratio for the duration of theenginestarting operation, and of subsequently and automaticallyselecting compression ratios approximately inversely proportionate tothe developed engine torque.

16. A cylinder for an internal combustion engine having a movable wall,spring actuated means cooperable to move the wall to decrease orincrease the firing chamber of the cylinder, and automatic meanscooperable to increase the spring pressure of said first means.

17. A multi-cylindered internal combustion en gine having manuallyadjustable cylinder heads, and fixed stops betweenwhich said heads areautomatically positioned. l

18. A multi-cylindered internal combustion engine having respectivecylinder heads, a rock shaft, and adjustable linkage connecting saidheads to the rock shaft.

ated piston cooperable with the spring of said able stops cooperablewith said lever.

1'2. A multi-cylindered internal combustion engine having movablecylinder heads, a rock shaft,

individually adjustable linkage connecting said heads to the rock shaft,a lever secured to said rock shaft, a fluid cylinder, a piston in saidcyl- 19. An internal combustion engine having a cylinder and acommunicating firing chamber, a. movable head in said ring chamber, aspring actuated lever cooperable with said head, an adjustable stop tolimit outward movement of said head, and manually adjustable meanslocated between said head and said lever.

20. An internal combustion engine having a cylinder and a firingchamber, a movable head in 'said firing chamber, a lever, manuallyadjustable means connecting said lever to said head, a cylinder having auid pressure supply source, apiston in said fluid cylinder adapted to beactuated by the iluid pressure therein, and a spring interposed betweensaid lever andV said piston.

` HERBERT J. KRATZER.`

13. An internal combustion engine having a

